(i'm new on this site so i apologize if this thread is not where it belongs..i will learn)

alright.i own a 6.2 litre diesel 20 suburban.1985 3/4 ton 4x4 6"lift! my transmission wasn't shifting correctly so i bought one from a guy who will not answer any of my questions......now in the begining i told him EVERYTHING about my sub and he said it will work,but later after i bought it he said he pulled the th400 from a 3/4 4x4 gasoline pick up.i also noted that it has about an inch or so shorter spline than my original transmission and a 3 bolt torque converter instead of the original 6 bolt(does that matter?)..i really don't know if there is a big difference between a th400 that came from a diesel or a gas. so that is one question


my second question is if this transmission WILL work in my diesel,how do i tell which torque converter i need? i still have the original torque converter from my first transmission so i thought i might be able to compare?

also i was wondering what the stamped numbers signify on the left side of the housing on the transmissions.my old trans had the number 28 stamped on it and the recent one has 26 stamped on it..what do those mean?!?!?!?!

Can you be more specific on "not shifting correctly"?

I have a '85 K30 with a TH400 and changed it from a 350 gas to 6.2 diesel. I re-built the tranny and put a shift kit in the valve body. The diesel converter I used bolted to the flex-plate with 6 bolts. A 3 bolt converter may be gas only. I also changed to a diesel specific governor. It shifts at normal speeds.



Could also be beginners luck.

:beerchug:

use your 6 bolt one the 3 bolt is gas. How do you know you need a new tranny? it could be other things. like vacuum line, pump modulator.

i took the old one out and put the newer one in already.when i got it up to about 30MPH with the original i had to hold the pedal all the way to the floor for a moment to make it grab the next gear-my 6 bolt converter looks like its got a little rust in it.if i use my original torque converter on the gas th400 it should work just like a regular diesel transmission??